Reversible covalent c-Jun N-terminal kinase inhibitors targeting a specific cysteine by precision-guided Michael-acceptor warheads.

There has been a surge of interest in covalent inhibitors for protein kinases in recent years. Despite success in oncology, the off-target reactivity of these molecules is still hampering the use of covalent warhead-based strategies. Herein, we disclose the development of precision-guided warheads to mitigate the off-target challenge. These reversible warheads have a complex and cyclic structure with optional chirality center and tailored steric and electronic properties. To validate our proof-of-concept, we modified acrylamide-based covalent inhibitors of c-Jun N-terminal kinases (JNKs). We show that the cyclic warheads have high resilience against off-target thiols. Additionally, the binding affinity, residence time, and even JNK isoform specificity can be fine-tuned by adjusting the substitution pattern or using divergent and orthogonal synthetic elaboration of the warhead. Taken together, the cyclic warheads presented in this study will be a useful tool for medicinal chemists for the deliberate design of safer and functionally fine-tuned covalent inhibitors.

Strain-Release-Driven Modular Synthesis of Oxetane-Based Amide Bioisosteres: Concise, Robust and Scalable Approach.

Amide bioisoterism is a widely used strategy in drug development to fine-tune physicochemical, pharmacokinetic, and metabolic properties, eliminate toxicity and gain intellectual property rights in uncharted chemical space. Of these, oxetane-amines offer particularly exciting possibilities as bioisosteres, although they are less frequently investigated than warranted due to the lack of simple and widely applicable synthetic methods. Herein, we report a two-step, practical, modular, robust, and scalable method for the construction of oxetane-containing amide bioisosteres that relies on the readily available oxetan-3-one. This operationally simple procedure exploits the enhanced reactivity of the keto group of the commercially available oxetan-3-one to form amine-benzotriazole intermediates, which springloaded adducts are then reacted with various aliphatic and aromatic organometallic reagents under mild conditions to afford various amino-oxetanes in good to high yields. The simplicity and broad applicability of the method greatly facilitates the synthesis of derivatives that were previously difficult or impossible to produce. The usefulness of this method in the field medicinal chemistry was also demonstrated by eliminating the well-known metabolic problem of ketoconazole.

Comprehensive investigation of the mutagenic potential of six pesticides classified by IARC as probably carcinogenic to humans.

Pesticides are significant environmental pollutants, and many of them possess mutagenic potential, which is closely linked to carcinogenesis. Here we tested the mutagenicity of all six pesticides classified probably carcinogenic (Group 2A) by the International Agency of Research on Cancer: 4,4'-DDT, captafol, dieldrin, diazinon, glyphosate and malathion. Whole genome sequencing of TK6 human lymphoblastoid cell clones following 30-day exposure at subtoxic concentrations revealed a clear mutagenic effect of treatment with captafol or malathion when added at 200 nM or 100 µM initial concentrations, respectively. Each pesticide induced a specific base substitution mutational signature: captafol increased C to A mutations primarily, while malathion induced mostly C to T mutations. 4,4'-DDT, dieldrin, diazinon and glyphosate were not mutagenic. Whereas captafol induced chromosomal instability, H2A.X phosphorylation and cell cycle arrest in G2/M phase, all indicating DNA damage, malathion did not induce DNA damage markers or cell cycle alterations despite its mutagenic effect. Hypersensitivity of REV1 and XPA mutant DT40 chicken cell lines suggests that captafol induces DNA adducts that are bypassed by translesion DNA synthesis and are targets for nucleotide excision repair. The experimentally identified mutational signatures of captafol and malathion could shed light on the mechanism of action of these compounds. The signatures are potentially suitable for detecting past exposure in tumour samples, but the reanalysis of large cancer genome databases did not reveal any evidence of captafol or malathion exposure.

Hungarian adaptation of the cerebellar cognitive affective/Schmahmann Syndrome Scale.

Recent studies have reported that cerebellar lesions can cause cognitive, behavioral, and affective symptoms. This constellation is called the cerebellar cognitive affective syndrome (CCAS). A bedside instrument, the CCAS-Scale, has been developed to screen for this clinical presentation. The aim of this study is to adapt the CCAS-Scale to Hungarian according to international cross-cultural guidelines. In cooperation with the senior author of the original CCAS-Scale, we defined a five-step adaptation protocol (license number 6758-1/2021). Step 1: translation of the scale from English to Hungarian by two separate teams. Step 2: comparison of the two translated versions, synthesis (preliminary version). Step 3: back translation by an independent professional translator. Step 4: authorization, revision, and correction. Step 5: pre-testing the scale, measuring the test times. Following our protocol, we produced the CCAS-H and the instructions booklet. We pre-tested healthy (n = 10) and cerebellar stroke patients (n = 10) and finalized the scale. Although not significantly, but cerebellar patients reached lower raw scores compared with healthy subjects. Testing times differed significantly between the two groups. A meticulous validation protocol was outlined to assess the validity and reliability of the newly adapted test. CCAS-H is a quick and adequate scale to examine the cerebellar-cognitive affective syndrome, which will be available for Hungarian professionals. Our main challenge was to define the stimuli and cues with adequate psycholinguistic and psychometric properties. As a next step, we are gathering data for the validation with the help of six other Hungarian Neurology departments.

Aspiration Risk Screening With Tongue Pressure Measurement in Acute Stroke: A Diagnostic Accuracy Study Using STARD Guidelines.

Introduction: Dysphagia can affect more than 50% of stroke patients in the acute phase. Aspiration pneumonia is a serious complication that can be prevented with dysphagia screening and assessment. Measurement of tongue elevation pressure is suggested to be a useful tool in aspiration risk screening. Objective: This study aimed to assess the diagnostic accuracy of maximum anterior tongue elevation strength (Pmax) in acute stroke care. Method: In this prospective study, data were collected in a neurology department (stroke center) where patients formed a consecutive case series. The sample consisted of thirty stroke patients who failed an initial dysphagia screening. Patients underwent anterior tongue elevation strength measurement (index test) during bedside dysphagia assessment by a speech-language pathologist and flexible endoscopic evaluation of swallowing (reference test) by an otorhinolaryngologist on the same day. Outcome variables (index values in kPa, reference values interpreted on the penetration-aspiration scale) were used for estimating measures of diagnostic accuracy in aspiration risk screening. Results: Ten patients aspirated on instrumental evaluation. At the cut-off point of ≤ 34 kPa the analysis showed 90% sensitivity, 35% specificity, 41% positive predictive value, and 88% negative predictive value. The area under the curve (AUC) for Pmax was AUC = 0.700 (95% CI [0.500-0.900]). Conclusion: Although individuals with low anterior tongue elevation strength tend to have a higher risk of aspiration, this variable alone is not capable of screening aspiration in acute stroke. In combination with a thorough noninstrumental bedside examination, it might have the potential to reduce the number of false positive cases. Further studies in this area would be worthwhile.

Application of Normal-Phase Silica Column in Hydrophilic Interaction Liquid Chromatography Mode for Simultaneous Determination of Underivatized Amino Acids from Human Serum Samples via Liquid Chromatography-Tandem Mass Spectrometry.

In neonatal screening, amino acids have a significant diagnostic role. Determination of their values may identify abnormal conditions. Early diagnosis and continuous monitoring of amino acid disorders results in a better disease outcome. An easy and simple LC-MS/MS method was developed for the quantitation of underivatized amino acids. Amino acids were separated using a normal-phase HPLC column having a totally porous silica stationary phase and using classical reversed-phase eluents. Mass spectrometry in multiple reaction monitoring mode was used for the analysis, providing high selectivity and sensitivity. A standard addition calibration model was applied for quantitation using only one isotope-labeled internal standard for all amino acids. Five calibration points were used for quantitation, and the method was successfully validated. The slopes of the calibration curves of the individual amino acids in parallel measurements were found to be similar. Since the measured slopes were reproducible, one serum sample could represent every series of serum samples of a given day. The method was tested on human serum samples and adequate results were obtained. This new method can be easily applied in clinical laboratories.

Synthesis and biochemical evaluation of 17-N-beta-aminoalkyl-4,5α-epoxynormorphinans.

Opiate alkaloids and their synthetic derivatives are still widely used in pain management, drug addiction, and abuse. To avoid serious side effects, compounds with properly designed pharmacological profiles at the opioid receptor subtypes are long needed. Here a series of 17-N-substituted derivatives of normorphine and noroxymorphone analogues with five- and six-membered ring substituents have been synthesized for structure-activity study. Some compounds showed nanomolar affinity to MOR, DOR and KOR in in vitro competition binding experiments with selective agonists [3H]DAMGO, [3H]Ile5,6-deltorphin II and [3H]HS665, respectively. Pharmacological characterization of the compounds in G-protein signaling was determined by [35S]GTPγS binding assays. The normorphine analogues showed higher affinity to KOR compared to MOR and DOR, while most of the noroxymorphone derivatives did not bind to KOR. The presence of 14-OH substituent resulted in a shift in the pharmacological profiles in the agonist > partial agonist > antagonist direction compared to the parent compounds. A molecular docking-based in silico method was also applied to estimate the pharmacological profile of the compounds. Docking energies and the patterns of the interacting receptor atoms, obtained with experimentally determined active and inactive states of MOR, were used to explain the observed pharmacological features of the compounds.

Effective targeting of breast cancer by the inhibition of P-glycoprotein mediated removal of toxic lipid peroxidation byproducts from drug tolerant persister cells.

Therapy resistance has long been considered to occur through the selection of pre-existing clones equipped to survive and quickly regrow, or through the acquisition of mutations during chemotherapy. Here we show that following in vitro treatment by chemotherapy, epithelial breast cancer cells adopt a transient drug tolerant phenotype characterized by cell cycle arrest, epithelial-to-mesenchymal transition (EMT) and the reversible upregulation of the multidrug resistance (MDR) efflux transporter P-glycoprotein (P-gp). The drug tolerant persister (DTP) state is reversible, as cells eventually resume proliferation, giving rise to a cell population resembling the initial, drug-naïve cell lines. However, recovery after doxorubicin treatment is almost completely eliminated when DTP cells are cultured in the presence of the P-gp inhibitor Tariquidar. Mechanistically, P-gp contributes to the survival of DTP cells by removing reactive oxygen species-induced lipid peroxidation products resulting from doxorubicin exposure. In vivo, prolonged administration of Tariquidar during doxorubicin treatment holidays resulted in a significant increase of the overall survival of Brca1-/-;p53-/- mammary tumor bearing mice. These results indicate that prolonged administration of a P-gp inhibitor during drug holidays would likely benefit patients without the risk of aggravated side effects related to the concomitantly administered toxic chemotherapy. Effective targeting of DTPs through the inhibition of P-glycoprotein may result in a paradigm shift, changing the focus from countering drug resistance mechanisms to preventing or delaying therapy resistance.

The first solid-state route to luminescent Au(I)-glutathionate and its pH-controlled transformation into ultrasmall oligomeric Au10-12(SG)10-12 nanoclusters for application in cancer radiotheraphy.

There is still a need for synthetic approaches that are much faster, easier to scale up, more robust and efficient for generating gold(I)-thiolates that can be easily converted into gold-thiolate nanoclusters. Mechanochemical methods can offer significantly reduced reaction times, increased yields and straightforward recovery of the product, compared to the solution-based reactions. For the first time, a new simple, rapid and efficient mechanochemical redox method in a ball-mill was developed to produce the highly luminescent, pH-responsive Au(I)-glutathionate, [Au(SG)]n. The efficient productivity of the mechanochemical redox reaction afforded orange luminescent [Au(SG)]n in isolable amounts (mg scale), usually not achieved by more conventional methods in solution. Then, ultrasmall oligomeric Au10-12(SG)10-12 nanoclusters were prepared by pH-triggered dissociation of [Au(SG)]n. The pH-stimulated dissociation of the Au(I)-glutathionate complex provides a time-efficient synthesis of oligomeric Au10-12(SG)10-12 nanoclusters, it avoids high-temperature heating or the addition of harmful reducing agent (e.g., carbon monoxide). Therefore, we present herein a new and eco-friendly methodology to access oligomeric glutathione-based gold nanoclusters, already finding applications in biomedical field as efficient radiosensitizers in cancer radiotherapy.

Transdermal Delivery of α-Aminophosphonates as Semisolid Formulations-An In Vitro-Ex Vivo Study.

α-Aminophosphonates are organophosphorus compounds with an obvious similarity with α-amino acids. Owing to their biological and pharmacological characteristics, they have attracted the attention of many medicinal chemists. α-Aminophosphonates are known to exhibit antiviral, antitumor, antimicrobial, antioxidant and antibacterial activities, which can all be important in pathological dermatological conditions. However, their ADMET properties are not well studied. The aim of the current study was to provide preliminary information about the skin penetration of three preselected α-aminophosphonates when applying them as topical cream formulations in static and dynamic diffusion chambers. The results indicate that aminophosphonate 1a, without any substituent in the para position, shows the best release from the formulation and the highest absorption through the excised skin. However, based on our previous study, the in vitro pharmacological potency was higher in the case of para-substituted molecules 1b and 1c. The particle size and rheological studies revealed that the 2% cream of aminophosphonate 1a was the most homogenous formulation. In conclusion, the most promising molecule was 1a, but further experiments are proposed to uncover the possible transporter interactions in the skin, optimize the topical formulations and improve PK/PD profiles in case of transdermal delivery.

Pharmacokinetics and Pharmacodynamics of Florfenicol in Plasma and Synovial Fluid of Pigs at a Dose of 30 mg/kgbw Following Intramuscular Administration.

A major problem of our time is the ever-increasing resistance to antimicrobial agents in bacterial populations. One of the most effective ways to prevent these problems is to target antibacterial therapies for specific diseases. In this study, we investigated the in vitro effectiveness of florfenicol against S. suis, which can cause severe arthritis and septicemia in swine herds. The pharmacokinetic and pharmacodynamic properties of florfenicol in porcine plasma and synovial fluid were determined. After a single intramuscular administration of florfenicol at 30 mg/kgbw, the AUC0-∞ was 164.45 ± 34.18 µg/mL × h and the maximum plasma concentration was 8.15 ± 3.11 µg/mL, which was reached in 1.40 ± 0.66 h, whereas, in the synovial fluid, these values were 64.57 ± 30.37 µg/mL × h, 4.51 ± 1.16 µg/mL and 1.75 ± 1.16 h, respectively. Based on the MIC values of the 73 S. suis isolates tested, the MIC50 and MIC90 values were 2 µg/mL and 8 µg/mL, respectively. We successfully implemented a killing-time curve in pig synovial fluid as a matrix. Based on our findings, the PK/PD breakpoints of the bacteriostatic (E = 0), bactericidal (E = -3) and eradication (E = -4) effects of florfenicol were determined and MIC thresholds were calculated, which are the guiding indicators for the treatment of these diseases. The AUC24h/MIC values for bacteriostatic, bactericidal and eradication effects were 22.22 h, 76.88 h and 141.74 h, respectively, in synovial fluid, and 22.42 h, 86.49 h and 161.76 h, respectively, in plasma. The critical MIC values of florfenicol against S. suis regarding bacteriostatic, bactericidal and eradication effects in pig synovial fluid were 2.91 ± 1.37 µg/mL, 0.84 ± 0.39 µg/mL and 0.46 ± 0.21 µg/mL, respectively. These values provide a basis for further studies on the use of florfenicol. Furthermore, our research highlights the importance of investigating the pharmacokinetic properties of antibacterial agents at the site of infection and the pharmacodynamic properties of these agents against different bacteria in different media.

An Unexpected Enzyme in Vascular Smooth Muscle Cells: Angiotensin II Upregulates Cholesterol-25-Hydroxylase Gene Expression.

Angiotensin II (AngII) is a vasoactive peptide hormone, which, under pathological conditions, contributes to the development of cardiovascular diseases. Oxysterols, including 25-hydroxycholesterol (25-HC), the product of cholesterol-25-hydroxylase (CH25H), also have detrimental effects on vascular health by affecting vascular smooth muscle cells (VSMCs). We investigated AngII-induced gene expression changes in VSMCs to explore whether AngII stimulus and 25-HC production have a connection in the vasculature. RNA-sequencing revealed that Ch25h is significantly upregulated in response to AngII stimulus. The Ch25h mRNA levels were elevated robustly (~50-fold) 1 h after AngII (100 nM) stimulation compared to baseline levels. Using inhibitors, we specified that the AngII-induced Ch25h upregulation is type 1 angiotensin II receptor- and Gq/11 activity-dependent. Furthermore, p38 MAPK has a crucial role in the upregulation of Ch25h. We performed LC-MS/MS to identify 25-HC in the supernatant of AngII-stimulated VSMCs. In the supernatants, 25-HC concentration peaked 4 h after AngII stimulation. Our findings provide insight into the pathways mediating AngII-induced Ch25h upregulation. Our study elucidates a connection between AngII stimulus and 25-HC production in primary rat VSMCs. These results potentially lead to the identification and understanding of new mechanisms in the pathogenesis of vascular impairments.

Unique, Specific CART Receptor-Independent Regulatory Mechanism of CART(55-102) Peptide in Spinal Nociceptive Transmission and Its Relation to Dipeptidyl-Peptidase 4 (DDP4).

Cocaine- and amphetamine-regulated transcript (CART) peptides are involved in several physiological and pathological processes, but their mechanism of action is unrevealed due to the lack of identified receptor(s). We provided evidence for the antihyperalgesic effect of CART(55-102) by inhibiting dipeptidyl-peptidase 4 (DPP4) in astrocytes and consequently reducing neuroinflammation in the rat spinal dorsal horn in a carrageenan-evoked inflammation model. Both naturally occurring CART(55-102) and CART(62-102) peptides are present in the spinal cord. CART(55-102) is not involved in acute nociception but regulates spinal pain transmission during peripheral inflammation. While the full-length peptide with a globular motif contributes to hyperalgesia, its N-terminal inhibits this process. Although the anti-hyperalgesic effects of CART(55-102), CART(55-76), and CART(62-76) are blocked by opioid receptor antagonists in our inflammatory models, but not in neuropathic Seltzer model, none of them bind to any opioid or G-protein coupled receptors. DPP4 interacts with Toll-like receptor 4 (TLR4) signalling in spinal astrocytes and enhances the TLR4-induced expression of interleukin-6 and tumour necrosis factor alpha contributing to inflammatory pain. Depending on the state of inflammation, CART(55-102) is processed in the spinal cord, resulting in the generation of biologically active isoleucine-proline-isoleucine (IPI) tripeptide, which inhibits DPP4, leading to significantly decreased glia-derived cytokine production and hyperalgesia.

Hungarian adaptation of an international swallowing screening method / Egy nemzetközi nyelészavarszurési módszer hazai adaptálása

Introduction: Swallowing disorders caused by stroke can affect half of the cases in the acute phase. The guidelines for nutrition therapy for stroke patients recommend several screening methods for swallowing disorders. The Gugging Swallowing Screen (GUSS) is one of the most widely used ones but has not been available in Hungarian until now. Objective: Adaptation and validation of the GUSS to Hungarian in acute stroke patients (GUSS-H). Method: Our research design was two-phased: for the adaptation, a five-step protocol was composed according to international guidelines. The second phase was the validation of the GUSS-H. For external validity, data from patients (n = 31) were compared to the reference values of the fiberoptic endoscopic evaluation of swallowing (FEES) for both dysphagia and aspiration risk. Internal validity was obtained by comparing data from two independent evaluators (n = 20). Results: According to the FEES results, dysphagia prevalence was 45%, aspiration prevalence was 32.3% in our sample. Inter-rater reliability was strong on both GUSS-H scores and severity of dysphagia (𝜅 = 0.899, p<0.001; 𝜅 = 0.801, p<0.001). The diagnostic accuracy of the test showed great results for both the risk of dysphagia and aspiration (sensitivity: 93%, 90%; specificity: 65%, 57%; positive predictive value: 68%, 50%; negative predictive value: 92%, 92%). Discussion: Compared to the original GUSS and other bedside screenings, GUSS-H performed better than average in terms of sensitivity and negative predictive value. It could predict the risk of dysphagia and aspiration, make recommendations for instrumental evaluation and dysphagia diet. Conclusion: Swallowing screening is one of the first steps of nutritional therapy for acute stroke patients which needs an interdisciplinary setting. With our study, GUSS-H is now available to Hungarian professionals.

Aspirin Mediates Its Antitumoral Effect Through Inhibiting PTTG1 in Pituitary Adenoma.

CONTEXT: DNA demethylation and inhibitory effects of aspirin on pituitary cell proliferation have been demonstrated. OBJECTIVE: Our aim was to clarify the molecular mechanisms behind the aspirin-related effects in pituitary cells. METHODS: DNA methylome and whole transcriptome profile were investigated in RC-4B/C and GH3 pituitary cell lines upon aspirin treatment. Effects of aspirin and a demethylation agent, decitabine, were further tested in vitro. PTTG1 expression in 41 human PitNET samples and whole genome gene and protein expression data of 76 PitNET and 34 control samples (available in Gene Expression Omnibus) were evaluated. RESULTS: Aspirin induced global DNA demethylation and consequential transcriptome changes. Overexpression of Tet enzymes and their cofactor Uhrf2 were identified behind the increase of 5-hydroxymethylcytosine (5hmC). Besides cell cycle, proliferation, and migration effects that were validated by functional experiments, aspirin increased Tp53 activity through p53 acetylation and decreased E2f1 activity. Among the p53 controlled genes, Pttg1 and its interacting partners were downregulated upon aspirin treatment by inhibiting Pttg1 promoter activity. 5hmC positively correlated with Tet1-3 and Tp53 expression, and negatively correlated with Pttg1 expression, which was reinforced by the effect of decitabine. Additionally, high overlap (20.15%) was found between aspirin-regulated genes and dysregulated genes in PitNET tissue samples. CONCLUSION: A novel regulatory network has been revealed, in which aspirin regulated global demethylation, Tp53 activity, and Pttg1 expression along with decreased cell proliferation and migration. 5hmC, a novel tissue biomarker in PitNET, indicated aspirin antitumoral effect in vitro as well. Our findings suggest the potential beneficial effect of aspirin in PitNET.

In vitro characterization of the furin inhibitor MI-1851: Albumin binding, interaction with cytochrome P450 enzymes and cytotoxicity.

The substrate-analog furin inhibitor MI-1851 can suppress the cleavage of SARS-CoV-2 spike protein and consequently produces significant antiviral effect on infected human airway epithelial cells. In this study, the interaction of inhibitor MI-1851 was examined with human serum albumin using fluorescence spectroscopy and ultrafiltration techniques. Furthermore, the impacts of MI-1851 on human microsomal hepatic cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6 and 3A4 activities were assessed based on fluorometric assays. The inhibitory action was also examined on human recombinant CYP3A4 enzyme and on hepatocytes. In addition, microsomal stability (60 min) and cytotoxicity were tested as well. MI-1851 showed no relevant interaction with human serum albumin and was significantly depleted by human microsomes. Furthermore, it did not inhibit CYP1A2, 2C9, 2C19 and 2D6 enzymes. In human hepatocytes, CYP3A4 was significantly suppressed by MI-1851 and weak inhibition was noticed in regard to human microsomes and human recombinant CYP3A4. Finally, MI-1851 did not impair the viability and the oxidative status of primary human hepatocytes (up to 100 µM concentration). Based on these observations, furin inhibitor MI-1851 appears to be potential drug candidates in the treatment of COVID-19, due to the involvement of furin in S protein priming and thus activation of the pandemic SARS-CoV-2.

Synovial and Systemic Pharmacokinetics of Florfenicol and PK/PD Integration against Streptococcus suis in Pigs.

Florfenicol is a member of the phenicol group, a broad-spectrum antibacterial agent. It has been used for a long time in veterinary medicine, but there are some factors regarding its pharmacokinetic characteristics that have yet to be elucidated. The aim of our study was to describe the pharmacokinetic profile of florfenicol in synovial fluid and plasma of swine after intramuscular (i.m.) administration. In addition, the dosage regimen of treatment of arthritis caused by S. suis was computed for florfenicol using pharmacokinetic/pharmacodynamic (PK/PD) indices. As the first part of our investigation, the pharmacokinetic (PK) parameters of florfenicol were determined in the plasma and synovial fluid of six pigs. Following drug administration (15 mg/kgbw, intramuscularly), blood was drawn at the following times: 10, 20, 30, 40, 50 and 60 min, 2, 3, 4, 5, 6, 7, 8, 12, 24, 48 and 72 h; synovial fluid samples were taken after 1, 2, 3, 4, 6, 8, 12, 24, 48 and 72 h. The concentration of florfenicol was determined by a validated liquid chromatography-mass spectrometry (LC-MS/MS) method via multiple reaction monitoring (MRM) modes. As the second part of our research, minimum inhibitory concentration (MIC) values of florfenicol were determined in 45 S. suis strains isolated from clinical samples collected in Hungary. Furthermore, a strain of S. suis serotype 2 (SS3) was selected, and killing-time curves of different florfenicol concentrations (0.5 µg/mL, 1 µg/mL and 2 µg/mL) were determined against this strain. Peak concentration of the florfenicol was 3.58 ± 1.51 µg/mL in plasma after 1.64 ± 1.74 h, while it was 2.73 ± 1.2 µg/mL in synovial fluid 3.4 ± 1.67 h after administration. The half-life in plasma was found to be 17.24 ± 9.35 h, while in synovial fluid it was 21.01 ± 13.19 h. The area under the curve (AUC24h) value was 54.66 ± 23.34 µg/mL·h for 24 h in plasma and 31.24 ± 6.82 µg/mL·h for 24 h in synovial fluid. The drug clearance scaled by bioavailability (Cl/F) in plasma and synovial fluid was 0.19 ± 0.08 L/h/kg and 0.29 ± 0.08 L/h/kg, respectively. The mean residence time (MRT) in plasma and synovial fluid was 24.0 ± 13.59 h and 27.39 ± 17.16 h, respectively. The steady-state volume of distribution (Vss) in plasma was calculated from Cl/F of 0.19 ± 0.08 L/h/kg, multiplied by MRT of 24.0 ± 13.59 h. For the PK/PD integration, average plasma and synovial fluid concentration of florfenicol was used in a steady-state condition. The obtained MIC50 value of the strains was 2.0 µg/mL, and MIC90 proved to be 16.0 µg/mL. PK/PD integration was performed considering AUC24h/MIC breakpoints that have already been described. This study is the first presentation of the pharmacokinetic behavior of florfenicol in swine synovia as well as a recommendation of extrapolated critical MICs of S. suis for therapeutic success in the treatment of S. suis arthritis in swine, but it should be noted that this requires a different dosage regimen to that used in authorized florfenicol formulations.

Mechanochemical synthesis of mononuclear gold(I) halide complexes of diphosphine ligands with tuneable luminescent properties.

A mechanochemical method is reported for the synthesis of Au(diphos)X complexes of diphosphine (diphos = XantPhos and N-XantPhos) ligands and halide ions (X = Cl and I). The Au(XantPhos)X (1: X = Cl; 2: X = I) and Au(N-XantPhos)Cl (3) complexes exhibited either yellowish green (1) or bluish green (2) emission, whereas 3 was seemingly non-emissive in the solid state at room temperature. Blue- (2B) and bluish green (2G) luminescent concomitant solvates of 2 were obtained by recrystallization. Luminescent colour changes from blue (2B) or bluish green (2G) to yellow were observed when these forms were subjected to mechanical stimulus, while the original emission colour can be recovered in the presence of solvent vapours. Moreover, the luminescence of 2B can be reversibly altered between blue and yellow by heating/cooling-cycles. These results demonstrate the power of mechanochemistry in the rapid (4 min reaction time), efficient (up to 98% yield) and greener synthesis of luminescent and stimuli-responsive gold(I) complexes.